/*******************************************************************************
* Copyright (c) 2005, 2014 springside.github.io
*
* Licensed under the Apache License, Version 2.0 (the "License");
*******************************************************************************/
package org.springside.examples.showcase.demos.hystrix.service;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.client.HttpStatusCodeException;
import org.springframework.web.client.RestTemplate;
import org.springside.examples.showcase.webservice.rest.UserDTO;
import com.netflix.hystrix.HystrixCommand;
import com.netflix.hystrix.exception.HystrixBadRequestException;
/**
* HystrixCommand的实现类, 将访问远程资源的逻辑封装在T run()函数内.
* 如需对异常, 超时, 短路等进行自行处理，返回默认值则实现T getFallback()函数.
*
* @author calvin
*/
public class GetUserCommand extends HystrixCommand<UserDTO> {
private static Logger logger = LoggerFactory.getLogger(GetUserCommand.class);
private RestTemplate restTemplate;
private Long id;
/**
* 构造函数，注入配置、用到的资源访问类和命令参数.
*/
protected GetUserCommand(Setter commandConfig, RestTemplate restTemplate, Long id) {
super(commandConfig);
this.restTemplate = restTemplate;
this.id = id;
}
/**
* 访问依赖资源的函数的实现。
*/
@Override
protected UserDTO run() throws Exception {
try {
logger.info("Access restful resource");
return restTemplate.getForObject("http://localhost:8080/showcase/hystrix/resource/{id}", UserDTO.class, id);
} catch (HttpStatusCodeException e) {
throw handleException(e);
}
}
/**
* 处理异常，对于客户端自己的异常，抛出HystrixBadRequestException，不算入短路统计内。
*/
protected Exception handleException(HttpStatusCodeException e) {
HttpStatus status = e.getStatusCode();
if (status.equals(HttpStatus.BAD_REQUEST)) {
throw new HystrixBadRequestException(e.getResponseBodyAsString(), e);
}
throw e;
}
}